I'm fairly new to salt water aquariums and I'm in the process of cycling my first reef tank (30 gals), fishless. I've done a bunch of research but still have questions..

I have two chunks of cured live rock sitting in my tank now, they weight total about 20-25lbs. I read that the surface is supposed to be cleaned? This is something I have not done, is this necessary? I've already noticed a lot of movement within the rock, some plants peek in and out, little crabs here and there, but the surface is pretty gray.

The tank is at 80F to help the cycle speed and I used salt water from the LFS to fill the tank

I have one last stupid question. After testing the water today, I got the following results:

pH: 7.9
ammonia: 0
Nitrites: 0
Nitrates: 0

Does this mean the tank has cycled?
Again, I started with 20lbs cured LR, LS and salt water from the LFS (which comes imported from the ocean). Also there are hitchikers on the rocks, including dusters and several crabs

Read up on the stages of cycling - you should see an ammonia spike, this will drop, then a nitrite spike, this will drop and finally, you'll start seeing nitrate. Ensure the Ammonia and Nitrite are zero (and you have a nitrate reading) before adding livestock.

I have one last stupid question. After testing the water today, I got the following results:

pH: 7.9
ammonia: 0
Nitrites: 0
Nitrates: 0

Does this mean the tank has cycled?
Again, I started with 20lbs cured LR, LS and salt water from the LFS (which comes imported from the ocean). Also there are hitchikers on the rocks, including dusters and several crabs

If the rock was truly cured, then you're not going to see any die off and your ammonia/nitrite/nitrate numbers will remain at zero with no spikes. You need to give it an ammonia source and see how the tank processes it. Throw in a cocktail shrimp or just some fish food and wait a couple days. If it's cured rock, then you shouldn't see any ammonia or nitrites, and your nitrates should start going up. If so, you're cycled and ready to go. If you see any ammonia or nitrites, then your rock was quite cured all the way or you ended up with more ammonia than you really needed and your tank is building up the required bacteria. In that case, wait out the cycle and when the ammonia and nitrites go back to zero you're good to go.

Last night I added some shrimp and other fish food and will wait for the whole cycle to process.

I'll also be purchasing a additive to balance the pH at ~8.2

There is a couple very small hairy crabs in the LR, should I trap it with the glass trick now or later? I also noticed a bigger one about 1/2 inch wide but not hairy eating off the LR.. not sure of his color though, but he seemed dark.